Organic Chemistry: Aromatics, Alcohols, Aldehydes, Ketones, Acids, Esters, Amines, Polymer, Study notes of Chemistry

Download Organic Chemistry: Aromatics, Alcohols, Aldehydes, Ketones, Acids, Esters, Amines, Polymer and more Study notes Chemistry in PDF only on Docsity! 1 22.1 Alkanes: Saturated Hydrocarbons 22.2 Alkenes and Alkynes 22.3 Aromatic Hydrocarbons 22.4 Hydrocarbon Derivatives 22.5 Polymers 22.6 Natural Polymers ← Biochemistry Chem 162A March 8 2006 Lecture/Jenekhe Chapter 22. Organic and Biochemical Molecules Computer model of a globular protein • Benzene, C6H6, is the prototype of aromatic compounds. An unsaturated cyclic hydrocarbon which is relatively less reactive compared to alkenes or alkynes. or + + + Cl2 HNO3 CH3Cl Cl NO2 FeCl3 H2SO4 AlCl3 + HCl + HCl CH3 Chlorobenzene Nitrobenzene Toluene E.g. delocalized π electrons - sp2 hybrid orbitals - Benzene undergoes Substitution Reactions - The products of these substitution reactions are monosubstituted benzene, with common names. - Systematic and common names with poly-substitution. 22.3 Aromatic Hydrocarbons 2 More Complex Aromatic Compounds ortho (o-) meta (m-) para (p-) X X X X X X 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 (o-)1,2 (m-) 1,3- (p-) 1,4- ．an organic semiconductor used in thin film transistors Some substituted benzenes and their names Pen tacenePentacene 22.4 Hydrocarbon Derivatives • Functional Groups - Atoms or groups of atoms that are part of an organic molecule and that exhibit characteristic chemistry, e.g. reactivity towards a particular reagent. ( See common functional groups in Table 22.4) • Alcohols - contain the hydroxyl (-OH) functional group. - nomenclature: replace the –e of the parent hydrocarbon with –ol. e.g. methane → methanol, CH3OH ethane → ethanol, CH3CH2OH In IUPAC naming, 3-Buten-2-ol OH is given a lower number CH2=CHCH2CH3 than C=C or halogen 1-Butene R CH2OH CHOH R R' R CR' R" OH H2C CHCH2CH3 OH Primary alcohol (1o) Secondary alcohol (2o) Tertiary alcohol (3o) 5 H3CC O OH + H-OCH2CH3 H3CC O OCH2CH3 + H2O acetic acid ethanol ethyl acetate - Names: alkyl prefix from the patent alcohol + replace –oic of parent acid with -oate H3CC O OCH2CH2CH2CH2CH2CH2CH2CH3 (common name: n-octyl acetate) n-octylethanoate C OH O OH + HO CCH3 O C OH O O + C O CH3 H2O Salicyclic acid Acetic acid Acetylsalicyclic aicd aspirin — Esterification reaction R1C O OH + H-OR2 R1C O OR2 + H2O acid alcohol Ester • Useful for the synthesis of polymers Esters • contain the functional group • synthesis: carboxylic acid + alcohol → ester C O O • Amines • Other Functional groups ( Not in Table 22.4) R1 N H C O R2 + H2OR1NH2 + HO C O R2 Amides E.g. H3C C O N CH2CH3 N-ethylacetamide (common name) N H C O amide group (also peptide bond) H Table 22.6 Some common Amines R NH2 R NH R' R N R' R" Primary amine (1o) Secondary amine (2o) Tertiary amine (3o) 6 22.5 Polymers • A polymer is a large molecule – “poly” many – “mer” part – also known as macromolecules – polymers typically have molar mass in the range of 105 to 107 g/mol • the enormous size of polymers has consequences for many physical and chemical properties – rapidly become solids with good strength – form unusual solutions (recall collegative properties of solutions) Greek “polymer” = many parts Polymers Synthetic Elastomers (Rubbers) natural Plastics (Thermoplastics) Thermosetting • adhesives • superglue Proteins / polynucleotides Polysaccharides (sugars) Gums Polymerization • A polymer-forming reaction is called polymerization Polymerization addition polymerization (chain-growth polymerization) ― addition polymers Condensation polymerization (step-growth polymerization) ― condensation polymers an example of a monomer • A monomer is a molecule that can be polymerized to give a polymer. • An addition polymerization consists of 3 different steps. i. initiation ii. propagation iii. termination free radical ionic etc. ― Addition Polymerization n CH2=CH2 n>> 103 ethylene catalyst C C H H H H n polyethylene 7 Free radical polymerization of vinyl monomers • Initiation CH2=CH2 + I · → free radical initiator generated by various ways • Propagation growing active chain • Termination (i) (ii) (iii) I C H 2C H H I CH2C H H + H2C CH2 I CH2 CH2 CH2 C H H I CH2 CH2 + H2C CH2C H H x I CH2 CH2 C H H x+1 I CH2 CH2 +C H H x C H H CH2 CH2 Iy I CH2 CH2 x+y+1 I Table 22.7 Some Common Synthetic Polymers, Their Monomers, and Applications 10 Conjugated Polymers: The 4th Generation of Polymers Conjugated Molecules • Have been around a long time with numberous examples from organic and biological chemistry (e.g. β-carotene, 11 conjugated double bonds; chromophore responsible for color vision; etc.) • Molecules composed of alternating single and double or triple bonds e.g. 1,3-butadiene 1,3,5-hexatriene benzene naphthalene anthracene pentacene biphenyl terphenylbenzene π- Conjugated Polymers: polymer semiconductors trans-polyacetylene, trans-PA poly(p-phenylene), PPP polypyrrole, PPy poly(p-phenylene vinylene), PPV polyquinoline, PPQ n n S n N n n N n S S S S N N N N H H H H H N Ph N Ph N Ph polythiophene, PT 11 N Ph N Ph N Ph S S S S S R R R R R R π-Conjugated Polymers Solar Cells, Photodetectors, Imaging technologies Chemical & Biosensors LEDs, Lasers Electrochromic Devices, Batteries Molecular Electronics Thin Film Transistors Photophysics Charge Transport Photoconductivity Conductivity Redox Properties Photophysics Luminescence Charge Transport Charge Transport Single-Molecule Charge Transport Electrochemistry Electronic Structure